new bike

I am college student, so therefore i have only a small budget for a hardtail mt bike. I want a decent hardtail for under 500, and have been on craigslist for a while, but am worried about buying a mountain bike used because of the possible abuse it would take. If in good condition would $300 for a fuji tahoe pro be a good deal, or should i just go buy a new bike like a giant or trek for around 500? Also sports authority has diamondback response pro for 410, but i get the feeling that because its an huge store that they don't get lots of respect or are as good comparatively because the components are not great.